A combine is a farm machine that harvests and threshes grain as it is driven through a field. The front portion of the combine that harvests the grain is commonly known as the head. A combine typically contains interchangeable heads to enable use with different grains, including corn, soybeans, and wheat. Modern heads are typically so wide that the combines are not safely driven on most roads. Accordingly, when the combine needs to be driven from one location to another location on a road, it is common practice to first remove the head from the combine, place the head lengthwise on a carrier, and then pull the carrier. The carrier is sometimes pulled by the combine and is sometimes pulled by a truck or tractor.
A carrier specially adapted for a head is commonly known as a head hauler. Heads vary in size and construction so head haulers generally contain adjustment means to adapt to the particular head. More particularly, head haulers typically contain two longitudinal rails upon which the head rests. At least one of these rails is typically adjustable in vertical elevation and transverse horizontal position. The adjustment of the rail typically requires tools and two or more persons.
Kuhns, U.S. Pat. No. 5,040,825, issued Aug. 20, 1991, which is incorporated by reference, discloses a first head hauler with a longitudinal rail whose vertical elevation and transverse horizontal position can be changed by a single person with tools. The adjustment mechanism includes an inclined bracket with a slotted sloped surface, an underlying plate, and an overlying plate that is attached to the movable longitudinal rail. The underlying plate and the overlying plate are attached to each other with nuts and bolts. When the plates are loosened relative to each other, they can be moved along the sloped surface which, in turn, moves the longitudinal rail.
Kuhns, U.S. Pat. No. 6,419,431, issued Jul. 16, 2002, which is also incorporated by reference, discloses a second head hauler with a longitudinal rail whose vertical elevation and transverse horizontal position can be changed by a single person without tools. This head hauler is illustrated in FIG. 1. As with the earlier Kuhns patent, the adjustment mechanism includes an inclined bracket with a slotted sloped surface, an underlying plate, and an overlying plate that is attached to the movable longitudinal rail. In this mechanism, the underlying plate and the overlying plate are attached to each other with a hook. When the hook is moved into a particular position, the plates are loosened relative to each other and they can be moved along the sloped surface. The movement of the plates, in turn, moves the longitudinal rail.
In both of the Kuhns head haulers, a moderate amount of effort is needed to move the longitudinal rail after the plates are loosened relative to each other. There is also a danger that plates will loosen at an undesired time (such as during transport when the head hauler passes over bumps) and the longitudinal rail will slide downwardly. Accordingly, there is a demand for a head hauler with an improved means for adjusting the vertical elevation and transverse horizontal position of the movable longitudinal rail. More particularly, there is a demand for an adjustment means that can be operated by a single person without tools with minimal effort and without any possibility of movement of the longitudinal rail at an undesired time.